The present invention relates to a lock, and more particularly to a non-contact chip lock being internally provided with a transmitting coil unit and to a key thereof being internally provided with an inductive choke. When the key is inserted into the lock, the inductive choke is induced by a magnetic field generated by the transmitting coil unit to produce electricity needed by the key to operate normally and to modulate and demodulate specially signals, such that the key is battery-free and encrypted data may be bi-directionally transmitted between the lock and the key.
It is a common practice for people to ensure the safety of their life and property by means of locks. Most of the conventional locks include mechanical-type lock barrel and key. For experienced thefts, such mechanical locks can be unlocked within one or two minutes. This can be evidenced by the quick unlocking of a lock by a locksmith. This undesirable fact is a great threat to people""s life and property. To improve the conventional mechanical-type locks, there are various kinds of electronic locks developed and available in the markets, including IC card lock, magnetic card lock, encrypted lock, wireless remote-controlled lock, etc. Such electronic locks are expensive and have big volume and are therefore inconvenient for carry. Some of these electronic locks need to replace batteries frequently and/or be isolated from magnetic articles. Users of such electronic locks would inevitably worry that the preset encrypted codes for the locks are illegally copied or decoded. All these factors prevent the electronic locks from being widely accepted by the public to replace the conventional mechanical locks.
The above-mention drawbacks of the conventional locks, either mechanical or electronic type, can be summarized as follows:
1. The conventional mechanical-type locks tend to be easily unlocked by those familiar with such skills.
2. The IC card and the magnetic card are provided with metal contacts or inducing magnetic strips which are possibly purposefully destructed by applying a wrong voltage or current to the metal contacts or demagnetizing the magnetic strips, so as to illegally unlock or damage the locks.
3. The encrypted codes for the encrypted lock are possibly detected by purposefully peeping at the lock when the same is being unlocked, or by observing keys on the lock having the sign of being frequently depressed.
4. The wireless remote-controlled lock needs frequent inspections and replacements of batteries. And, the encrypted signals emitted via radio waves are possibly purposefully copied by someone else in an attempt to decode and unlock the lock.
It is therefore tried by the inventor to develop a non-contact chip lock and a battery-free key thereof to eliminate the drawbacks existing in the conventional mechanical and electronic locks.
A primary object of the present invention is to provide a non-contact chip lock and a battery-free key thereof, wherein the key does not need any battery to supply electricity needed by it to operate normally and allows bi-directional transmission of encrypted data between the key and the lock.
Another object of the present invention is to provide a non-contact chip lock and a battery-free key thereof, wherein the key is non-directional relative to the lock and allows easy insertion of it into the lock without the need of turning it to any specific position in the lock.
To achieve the above and other objects, the non-contact chip lock of the present invention is provided with an internal circuit composed of a microcontroller, a comparator, a transmitting coil unit, a position switch, and an unlocking unit, and the key thereof is provided with an internal circuit composed of a microprocessor, a residual magnetism eraser, an inductive choke, a rectifying and stabilizing unit, and an electric pulse counting unit. When the key is inserted into the lock, the inductive choke in the key is induced by a magnetic field generated by the transmitting coil unit in the lock and together with the transmitting coil unit forms a flyback transformer. The induced inductive choke generates electricity needed by the key to operate normally, and no battery is needed by the key. With the induced current generated by the inductive choke in the key, encrypted data may be bi-directionally transmitted between the key and the lock, and the key could be easily inserted into the lock without the need of turning the key to a specific position in the lock.